Nucleophilic Substitutions of 2-Halonaphtho(2,3-b)furan-4,9-diones and 2-Nitronaphtho(2,3-b)furan-4,9-dione.
作者:Jyunichi KOYANAGI、Katsumi YAMAMOTO、Kouji NAKAYAMA、Akira TANAKA
DOI:10.1248/cpb.45.1579
日期:——
2-Chloronaphtho[2, 3-b]furan-4, 9-dione (4) was allowed to react with sodium phenoxide to produce 2-phenoxynaphtho[2, 3-b]furan-4, 9-dione (8) in 55% yield. Also, in a similar manner, 8 was obtained from the reactions of 2-bromonaphtho[2, 3-b]furan-4, 9-dione (5), 2-iodonaphtho[2, 3-b]furan-4, 9-dione (6) and 2-nitronaphtho[2, 3-b]furan-4, 9-dione (7) with sodium phenoxide. The reaction of 4 with sodium methoxide gave methyl 3-hydroxy-1, 4-naphthoquinone-2-acetate (9) in which the furan ring was cleaved. 2-Phenylthionaphtho[2, 3-b]furan-4, 9-dione (11) and 2-methylthionaphtho[2, 3-b]furan-4, 9-dione (12) were obtained from the reactions of 4 with thiolates in 63% and 62% yields, respectively. Furthermore, 4 was treated with sodiomalonic ester ot give diethyl 2-(naphtho[2, 3-b]furan-4, 9-dione-2-yl)malonate (13) in 28% yield. Compound 13 was also obtained from the reactions of 5 and 7 with sodiomalonic ester. All these nucleophilic substitutions were carried out at room temperature. It was found that 4-7 had a high reactivity with various nucleophilic reagents.
让 2-氯萘并[2,3-b]呋喃-4,9-二酮(4)与过氧化钠反应生成 2-苯氧基萘并[2,3-b]呋喃-4,9-二酮(8),收率为 55%。同样,2-溴萘并[2,3-b]呋喃-4,9-二酮 (5)、2-碘萘并[2,3-b]呋喃-4,9-二酮 (6) 和 2-硝基萘并[2,3-b]呋喃-4,9-二酮 (7) 与亚苯基氧化钠反应也可以得到 8。4 与甲醇钠反应生成 3-羟基-1,4-萘醌-2-乙酸甲酯(9),其中的呋喃环被裂解。4 与硫醇盐反应得到 2-苯基硫代萘并[2,3-b]呋喃-4,9-二酮(11)和 2-甲基硫代萘并[2,3-b]呋喃-4,9-二酮(12),产率分别为 63% 和 62%。此外,将 4 与十二丙二酸酯进行处理,可得到 2-(萘并[2, 3-b]呋喃-4, 9-二酮-2-基)丙二酸二乙酯(13),收率为 28%。化合物 13 也是由 5 和 7 与 sodiomalonic 酯反应得到的。所有这些亲核取代反应都是在室温下进行的。研究发现,4-7 与各种亲核试剂具有很高的反应活性。